Press



March 27, 1956 w. STRAUSS PRESS 7 Sheets-Sheet 1 Filed NOV. 1, 1951 INVENTOR ATTORNEY amh 27, 1956 w. STRAUSS PRESS 7 Sheets-Sheet 2 INVENTORFiled Nov. 1, 1951 March 27, 1956 w. sTRAuss PRESS 7 Sheets-Sheet 3Filed NOV. 1, 1951 W. STRAUSS March 27, 1956 PRESS Q m D K Filed Nov. 1,1951 mm, a; an

ATTORNEY March 27, 1956 w, STRAUSS 2,739,349

PRESS Filed Nov. 1, 1951 7 Sheets-Sheet 5 Fzi). 9.

INVENTOR WJJLmn Strauas dim, gig/ J & Wam

ATTORNEY March 27, 1956 w. STRAUSS PRESS trazzss BY aid... 4 4 32...,

ATTORNEY March 27, 1956 w. STRAUSS 2,739,349

PRESS Filed Nev. l, 1951 7 Sheets-Sheet '7 Fri-@171. 7 60 INVENTORWillianz Strauss 0m-d dMx ATTORNEY United States Patent PRESS WilliamStrauss, Philadelphia, Pa., assignor to F. J. Stokes Machine Company,Philadelphia, Pa., a corporation of Pennsylvania Application November 1,1951, Serial No. 254,226

14 Claims. (Cl. l8--30) My invention relates to a new machine formolding articles from plastic material in a manner which insurescontinuous and efiicient operation. More particularly my inventionrelates to an injection molding press uniquely constructed to completelyeliminate the usual shut-down periods caused by failure in the solidmolding material removal operation, thereby enabling a large number ofmy machines to be operated by a single attendant.

In the past, considerable research and development work has beenundertaken to produce a truly continuous injection molding press. One ofthe greatest obstacles has been the development of apparatus forpositively and completely removing all of the solidified moldingmaterial from the dies. While meritorious advance has been made in thisdirection, it is significant to note that substantially equal activityhas been directed toward the development of accurate checking devicesfor stopping the press upon failure of the previously developed solidmaterial removal devices. It will be readily appreciated that thesedevices are quite complicated and involve a substantial initialinvestment, but the industry has found it necessary to accept this addedcost to insure adequate protection of the dies which are, of course,quite expensive. in practice, it has been found that the continuouspresses now in use require considerable attention due to stoppagescaused by failure of the removal means, thereby limiting considerablythe number of presses which may be operated by a single attendant. Insummary therefore, it appears that developments in the continuousinjection molding art have been compromising in nature and that a trulycontinuous horizontal injection molding press has not been developed toa degree acceptable to the industry.

My invention positively overcomes the past difficulties and facilitatesthe operation of considerably more presses by a single attendant throughthe provision of a press including a removal means capable of completelyand positively removing the solid molding material from the dies and thespace between the dies in a certain and reliable manner. Further, mypress is capable of degating the desired molded pieces during theremoval operation thereby eliminating the expensive separate degatingoperation which has plagued the injection molding industry. This degatinoperation is accomplished by my press without sacrifice of the highreliability of the removal operation.

I accomplish the removal operation through a removal means whichincludes an independently operated ejection means for disengaging thesolid material from one of the dies, and a stripper mechanism whichsevers the sprue thread formed when the dies are parted, covers the faceof the other die to prevent contact of removed solid material therewith,and completely disengages the solid material from the ejection means.The ejection means is mounted in the main power ram which reciprocatesthe movable die and has an independent hydraulic system whereby ejectorpins and a sprue base holder may be moved outwardly from the die face topush the solid material away from the die irrespective of the positionof the movable die. After the ejection means has reached its fullyextended position, the stripper mechanism moves in transversely of thelongitudinal center line of the machine to cut the sprue threadextending from an orifice in the face of the fixed die by means of asprue cutter. Certain molding materials are prone to produce a rathertenacious sprue thread which must be cleanly severed at the orifice in areliable manner to positively insure its complete removal from the spacebetween the molds. Therefore, I have provided a means for biasing thesprue cutter into slidable engagement with the die face and over theorifice whereby the proper amount of cutting pressure is applied toinsure the clean severance of even the toughest sprue thread.

After the sprue thread has been cut, the stripper mechanism continuesacross the space between the dies to a fully extended position wherein adie protecting cover is positioned between the die face of the fixed dieand the solid molding material, and a comb is positioned astraddle theejector pins and the sprue base holder. Upon retraction of the ejectionmechanism, the solid material is sprung free of the sprue base holderand falls through a trajectory path into an appropriate receptacle. Thedie protecting cover interrupts the trajection of any solid materialtraveling toward the fixed die face and thereby prevents contact of thesolid material therewith.

Degating of the desired molded articles is accomplished in my inventionby the provision of cutter blades mounted on the comb which areappropriately positioned to contact the joints between the desiredmolded articles and the gates just prior to the engagement of the solidmolding material with the face of the comb. In this manner the jointsare cut and the desired articles fall away from their gates before theremaining solid molding material, that is, the sprue and gates, contactsthe comb for the stripping operation.

Degating during the initial extending movement of the ejection means mayalso be accomplished by my invention. The solid molding material issomewhat flexible immediately after the dies are parted, due to the warmcondition thereof, and I have discovered that the gates may be flexedconsiderably at this stage without breakage. By the provision ofrestraining means at the gate portions, the initial extending movementof the ejector pins and the sprue base holder cause the desired moldedarticles and portions of the gates to be flexed away from the die facewhile other portions of the gates are restrained. Before releasing therestrainment of these gate portions, the joint between the gates and thedesired articles reach their breaking point thereby allowing the desiredarticles to fall free. In practice, I have found this feature of myinvention to work very well by the provision of outwardly angularlydisposed gate restraining holes in the die face by which gate leg endsare rerained upon initial extension of the ejection means, the centralportion of the gate being bowed outwardly until degating occurs afterwhich the gate extensions spring free of the restraining holes to allowcompletion of th removal operation.

I have found that for some types of molding operations, it is notnecessary to have a die protecting cover which covers the entire face ofthe fixed die. The reason for this is that only the solid materialpositioned at the upper part of the movable die follows a trajectorypath toward the fixed die face. The lower solid material drops out ofthe space between the dies and presents no problem.

Other further and more specific: objects of this invention will becomeapparent from a consideration of the following description when taken inconjunction with the accompanying drawings wherein;

Fig. 1 is a side elevational view of my improved moldmg machine;

Fig. 2 is a plan view of my machine;

Fig.3 is a view taken on line 33.of Fig. 2 rotated to the uprightposition;

Fig. 4 is a view taken on line 4-4 of Fig. 2 rotated to the uprightposition;

Fig. 5 is a view taken on line 55 of Fig. 2 and rotated to the uprightposition; Q

Fig. 6 is a view taken on line 6-6 of Fig. 5;

Fig. 7 is a view taken on line 77 of Fig. 5;

Fig. 8 is an enlarged vertical longitudinal midsectional view of theleft end of the machine as viewed in Fig. 1, showing the hydraulic powermeans and the movable mold member;

Fig. 9 is an enlarged vertical longitudinal midsectional view of theright end of the machine as viewed in Fig. l, and showing the plasticheating and injection means;

Fig. 10 is a wiring diagram for my machine suitable for controllingmanual, semi-automatic, or automatic operation;

Fig. ll is an enlarged front elevation showing the stripper and covermechanism fully extended and the ejector mechanism partially retracted;

Fig. 12 is a perspective view of a movable die member designed to degatethe molded pieces immediately upon ejection of the solid molded materialtherefrom;

Fig. 13 is a sectional view taken on line 13-13 of Fig. 12; and

Fig. 14 is a view similar to Fig. 13 but showing the ejector mechanismin a partially extended position.

Referring now to Figs. 1-8, it will be seen that my machine has a baseon which is rigidly mounted an abutment 21 from which extends a lowertie rod 22 and an upper tie rod 23, the inner ends of these tie rodsbeing anchored to a fixed platen 24 of a fixed press member 49 rigidlymounted'on the base 20. A movable press member 19, having platen 25, isslidably mounted on the tie rods 22 and 23 and is rigidly fixed to themain power ram 26 through the horizontally spaced side arms 48.Cooperating dies 39 and 40 are part of the fixed and movable pressmembers respectively, and are appropriately removably secured to theopposing faces of the fixed platen 24 and the movable platen 25,respectively. As seen more clearly in Fig. 8, the hydraulic power unit92 includes the main power ram 26 which has a piston 27 at its outer endpositioned in a main cylinder 23. By appropriate regulation of hydraulicpressure through supply conduits 29 and 30 the movable platen 25 iscaused to move horizontally to' and from a closed position with thefixed platen.

The inner end of the main power ram 26 has an opening'therein whichforms an ejector cylinder 31 for housing the ejector piston 32 of anejector mechanism. This ejector mechanism provides for the ejection ofmolded parts from the movable die irrespective of the position of themain power ram through an ejector piston rod 33 rigidly connected to anejector plate 34 which is in turn connected to bars 35 slidablypositioned in the movable member. Rigidly ailixed to these bars 35 is anejector pin plate 36 on which are mounted a plurality of ejector pins3'7 and a knotched sprue base holder 38, which pass through appropriatepassages in the movable die 40. Suitable hydraulic lines 41 and 42 areprovided for powering the ejector mechanism.

Housed within the base 20 is an appropriate hydraulic pump (not shown)for applying a predetermined relatively low pressure to the movablemember 19 until it reaches a partially closed position at which time ahydraulic booster pump (not shown) applies a relatively high pressure tomove the movable platen'from the partially closed position to a fullyclosed position for injection of the molding material. By thisarrangement the complete closing of the die members is avoided ifmaterial is present between-the mating facesof the die mem bers as willbe more fully explained hereinafter.

c f e Wi d il s? W3 5i}? fixed 4 The injection mechanism for feedingfluent molding material to the mold, shown enlarged in Fig. 9, isconnected to the fixed platen 24 in fluid communication with the fixeddie member 39 and has a hopper 16 from which material flows in measuredquantities past a feed piston 41 into a feed cylinder 42 The material isthen drawn back and dropped into heating cylinder 43 and fed inwardly byan injection plunger. 44 into the mold. The injection piunger44 ishydraulically operated through the injector hydraulic means, 18.Suitable heating means (not shown), such as'electrical or hot oilheating means, is preferably mounted around theheating chamber 45 toaccomplish the heating necessary to fluidize the molding material, anda'spreader 47 is positioned in the center of the plasticizing chamber toinsure uniformity of heating. Enough material for several molding cyclesis present in the heating cylinder 43 at any given time and the newlyintroduced material becomes'increasingly plasticized as it approachesthe injection nozzle 17 under the injection and stuffing action of theinjection plunger 44.

A stripper mechanism 50 (Figs. 5-7) is mounted on an upper slide rail 51and a lower slide rail 52 for adjustable movement along the longitudinalaxis of the machine. The stripper mechanismSl) has a housing 53 whichencloses a power means for moving a die protecting cover 54 into and outof the space between the die members when parted. ,The die protectingmeans 54 prevents ejected solid material from contacting and residing onthe vertical mating face of. the fixed die member 39 and therebypositively avoids all shutdowns arising from the solid material removaloperation. A sprue cutter 55 is mounted on. the die protecting cover 54for movement into slidable engagement with the fixed die member 39 forcutting the sprue threadextending therefrom when the dies are parted.vThepower means, which also reciprocates a stripper comb 139 between thedies, has a hydraulically powered cylinder 56, mounted on the housing53, which reciprocates a carriage 5.7 through the piston rod 58 andtheangle connector 59, the carriage 57 being guided in its movements byanadjustable upper. guide 6% and a lower track 61. As seen in Fig. 7,the upper guide 69 has a main bar 62 and a cover bar 63 which are joinedby studs 64 to form a slot in which the upper edge of the carriage 57 isslidablyretained. By means of the adjusting studs 65 and the enlargedholes in the main bar 62 through which studs 64 pass, the properclearance may be set to insure smooth reciprocating movement of thecarriage S7.

The die protecting cover 54 is pivotally mounted on the carriage 5'7through an upper bearing block 66 and a lower bearing block 15 which aremounted on cooperating journal blocks 67 and 68, respectively, aifixedto the carriage 57.

The lower bearing block 15 has a roller arm 69 which extends along thecarriage 57 and is connected thereto at its end portion by a springmeans 70. Under the action of the spring 79 the sprue cutter 55 isbiased toward the sprue orifice in the fixed die 39. To control themovement of the sprue cutter'55 toward and away from the fixed die 39 bythe spring means 70, a guide rail 7'1 is provided which restrainspivotal movement of the cover member 54 until the sprue cutter 55 isclose to the sprue orifice, at which time the roller 140 contacts theangular cutaway portion 72 of the guide rail 71 thereby allowing thespring 70 to pivot the cover member and bring the sprue cutter intoengagement with the face of the die member 39. As seen in Fig. 2, thesprue cutter 55 is yieldably urged into sliding engagement with the faceof die member 39 by the spring 70, thereby eliminating the need ofcomplicated adjusting devices for preventing damage to the die. i itwill be appreciated also that the angular cutaway portion 72 "of theguide rail 71 eliminates all but the required amount of abrasive slidingcon- Referring now to Fig. 11, it will be seen that despite cutter 55has just severed the sprue thread and that the cover member 54 is movingacross the face of the fixed die 39 to interrupt the trajectnry path ofthe solid molded material as it is removed by ejection and stripping.Upon return of the knotched sprue base holder 38 into the movable die40, the complete molded structure of solid molding material is drawntoward the comb 139 which is equipped with cutter blades 73, the bladesbeing arranged to contact and sever the joint between each of the moldedparts and its gate before any part of the molded structure contacts thecomb. In this manner, the desired molded article is cleanly andcompletely degated in an efiicient and automatic manner.

A degating arrangement is shown in Figs. 12-14, which causes the desiredmolded articles to be ejected gatefree from the mold prior to the spruecutting and stripping operation. The movable die has the usual spruebase hole 141 and gate passages 142 and is further equipped withangularly disposed gate restraining means or holes 143. Upon initialmovement of the ejection means, the ejector pins 37 engage the desiredmolded articles and move them away from the movable die 40, and theknotched sprue base holder 38 similarly moves the sprue and the centralportion 144 of the gate away from the movable die. The outer ends 145 ofthe gate arms 146 are releasably retained in the angularly disposedholes 143, thereby causing the gate arms 146 to bow as shown in Fig. 14.The bowing of the gate arms 146 under the action of the ejection meansand the gate restraining means causes the breakage of the gate from thedesired molded article at the joint therebetween. The removal of theremaining solid molding material may then be accomplished in the mannerpreviously described.

Contacting, making and breaking devices may be arranged at various partsof my machine to operate relays for the control of suitabletime-controlled valves so that the sequence of operation will follow inthe proper order and with the proper timing. In Fig. is shown the wiringdiagram for my machine which permits operation either by hand,semi-automatically or completely automatically. It will be noted that asafety switch 75 is provided which must be closed by the operator beforethe press is placed in operation. This switch may be in the form of anappropriate safety gate of any suitable design. Fig. 10 shows thecontrol switches in the positions assumed when the machine is completelyshut down and the safety gate is open.

In hand operation, any single moving member of the press may be actuatedby tripping its control switch. All circuits are safety interlocked,that is, a movable member cannot be actuated unless all other movablemembers are in their proper positions.

In semi-automatic operation, the electrical circuit is arranged toautomatically produce the molded structure and open the press to allowoperator control of the ejection mechanism and the stripper and covermechanism 50.

In automatic operation, the press is sequence operated, that is, thecompletion of the stroke of one movable memher will complete the circuitfor actuating the member of the succeeding operation.

To facilitate an explanation of the wiring diagram and the operatingsequence of my machine, it will be assumed that the safety switch 75 isclosed, the press is set for hand operation, and it is desired to startan automatic cycle. To accomplish this, it is necessary that switch 76,which allows manual control of the movable platen, be in the openposition. Also, switches 77, 78 and 79, which allow manual control ofthe injector mechanism, the stripper and cover mechanism, and theejector mechanism respectively must be in the Reset or Open position.

To start the completely automatic operation of my press, switch 80 ismoved to Automatic, thereby opening contacts 82, 84, 86 and 88 andclosing contacts 81, 83, 85, 87, 89 and 90. The timer 91 is started whencontacts 83 are closed for regulating the length of time the pressremains closed for cooling the molded articles. Through contacts 81 thevalve magnet 93 is energized to allow the movable platen 25 to be movedto a partially closed position by the hydraulic power unit 92.

As soon as the press starts closing, switch 94 is released to closecontacts 95 and energize relay 96 which remains energized until andduring part of the removal operation through holding contacts 97 andswitch 93.

A safety feature is included in my machine which prevents destruction ofthe die members by a high pressure advance of the movable platen 25toward the fixed platen 24 when any obstructions such as unejected partsare present between the die members. As previously explained, themovable platen is moved to a partially closed position by low hydraulicpressure. Upon reaching this position, switch 99 is closed to energizethe booster valve magnet 100 which causes a hydraulic booster to producea high pressure for completely closing the press and maintaining it inthis position during the injection cycle and cooling period.

When the movable platen reaches the fully closed position, the highpressure closes pressure switch 101 which starts timer 1413 throughswitch 85. Closing pressure switch 191 also completes a circuit throughcontact 104 in timer 103 to energize valve magnet 105 which causes theinjection plunger 44 to be moved inwardly thereby forcing material intothe mold cavity. At the time the injection plunger 44 advances inwardly,the feed piston 41 is carried inwardly a predetermined distance to allowraw material to flow into the feed cylinder 42 from whence on the returnstroke, it is dropped into the heat ing cylinder 13. When the injectionplunger has moved inwardly the required distance, switch 106 is trippedclosed thereby energizing relay 107. The injection plunger will remainin this inward position for the time period of timer 193, at the end ofwhich contact 104 will open de-energizing valve magnet 1115 therebyreturning the injection plunger to reset position. When the injectionplunger returns to reset position releasing switch 106, the relay 107 isheld closed through holding contacts 168 and switch 98.

The opening of contact 1114 closes contact 169 to start timer 110 andcomplete the circuit through contacts 111 thereof. On reaching its resetposition, the injection plunger also trips switch 112 to energize relay114 thereby energizing the valve magnet 1115 again through contacts 115to cause the injection plunger to move inwardly again for the stuffingoperation. As soon as the plunger 44 starts to advance, switch 112 isreleased to open position, the holding circuit for relay 114 beingaccomplished through switches 111 and 1119.

When timer 111) times out, switch 111 will open deenergizing relay 114and opening contact 115 thereby deenergizing valve magnet 105 to returnthe injection plunger to Reset position.

The press will then remain closed until timer 91 runs out to completethe cooling of the molded articles. At the end of this cooling time,switch 116 will open deenergizing valve magnet 93, thereby causing themovable platen to be moved outwardly to its open position. When themovable platen reaches full open position, switch 9 1 is tripped toengage contact 117 to energize valve magnet 118 which causes the ejectorpins 37 and sprue base holder 33 to push the molded structure away fromthe movable die 4-0. When the ejector mechanism reaches its completelyadvanced or extended position, switch 119 is tripped to close contacts121) and hold relay 121, which is made possible through contacts 122 ofswitch 123 which are closed when the ejector mechanism advancesinitially and through relay 1117 which is being held closed at this timeas explained above. With the ejector mechanism in the fully advancedposition and switch 119 tripped, the circuit is completed to energizevalve magnet 124 which causes the stripper mechanism to be advancedbetween. the .dies, the stripper comb 139 being astraddle the extendedejector pins and sprue base holder. As the cover 54 moves in, the spruecutter 55 severs the sprue thread at the face of the fixed die 39 aspreviously explained.

After the sprue thread has been completely severed from the fixed die 39and the die protecting cover 54 has moved across the fixed die toprotect the face thereof, the ejector mechanism is withdrawn therebypulling the molded structure into abutting engagement with the strippercomb 139. It will be understood that cover members may be of varioussizes to cover the upper portion of the die or the Whole die asrequired. This is accomplished upon the opening of switch 98 when thestripper mechanism reaches thefully extended position between the dies.When switch 98 is opened, the holding circuit of relay 96is interruptedthereby tie-energizing the valve magnet 118 which causes the ejectormechanism to be withdrawn to its reset position within the movable die40. Also, upon opening switch 98, the holding circuit of relay 107 isinterrupted.

Upon reaching'its reset position, the ejector mechanism trips switch 123away from contacts 122 to interrupt the holding circuit of relay 121 andde-energize valve magnet l24 to cause the stripper mechanism to returnto reset position within housing 53. On reaching reset position, thismechanism trips switch 125 closed to complete the circuit to start timer91 and begin a new cycle.

If an obstruction exists between the mold members, the movable member 19will not reach the partially closed position to close switch 99, andtherefore no high pressure will be applied to move the movable member tothe fully closed position. The press will remain in the partially closedposition until timer 91 times outat which time the press will open, theejector mechanism will advance, and then all operation of the press willstop, because =the normal electrical sequence has been interrupted.

It the injection plunger 44 does not advance inwardly the requireddistance, a short shot and a partially filled mold is the result. Switch106 will not be tripped by the injection plunger 44 and the press willstop after opening and ejecting the pieces, because normal electricalsequence was interrupted.

To accomplish complete disconnection of my machine from all powersources upon automatic stoppage due to an interruption of the normalcycle, I have provided a delay timer 126 which starts timing at the samemoment as timer 91, but which is set to run for a longer period of timeso that it will not completely time out during normal operation. By thisarrangement, switch 127 of delay timer 126 remains closed to maintainenergization of relay 130 which completes the circuits to the heaters(not shown) of the molding material heating cylinder 43 and the mainpower source of the press through switches 128 and 129, respectively. Ifthere be any interruption of the normal cycle, the press will stop afteropening and removing the pieces. Delay timer 126 will then time out,opening switch 127 and de-energizing relay 130. Upon the de-energizationof relay 1330, switch 128 will be opened to prevent burning of thematerial in the heating cylinder and switch 129 will be opened to securethe main power source, thereby preventing accidental movement of anymembers during repair work. An alarm switch 131 may also be provided tosignal the complete disconnection of my machine from all power sources.

It will be readily appreciated that the contact making and breakingdevices shown in Fig. 10 are appropriately mounted on the press foractuation by their respective elements of the press when these elementsreach their predetermined positions as described hereinbefore.

While I have described a preferred form and application of my invention,I do not wish to be limited or restricted to the specific details hereinset'forth, but wish .to cover all changes :andrnodific ations which donot constitutedepartures-from the spirit and scope ,of my invention. i fl l. in an injection molding press, the combination of first and secondrelatively movable press members, each having a die, thedie of thesecond press member having an orifice in its face-through which fluentmolding material is delivered, means positioned in said first die forwithdrawing the resultant sprue from said orifice as the press membersare parted thereby forming a sprue thread extending from said. sprueinto said orifice, and means for severing said sprue thread at saidorifice including a movable cutter blade adapted for slidable contactwith said face over said orifice.

2. In arr-injection molding press, the combination of first and secondrelatively movable press members, each having a die, the die of thesecond press member having an orifice in its face through which fluentmolding material is delivered, and removal meansfor completelydisengaging the solid molding material from the die of the first pressmember after the press members are parted, said removal means includingmeans for severing the resultant sprue thread extending from saidorifice.

3. In a horizontal injection molding press, the combination of first andsecond relatively movable press members, each having a die, the die ofthe second press memberhaving an orifice through which fluent moldingmaterial is delivered, and removal means for completely disengaging thesolid molding material from the die of the first press member after thepress members are parted, said removal means including a vertical dieprotecting cover for covering the upper portion of the second die andmeans for moving said cover into the space between the press members toprevent contact of the removed solid molding material with the die ofsaid second press member.

4. In a horizontal molding press, the combination of first and secondrelatively movable press members, each having a die, the die of-saidsecond press member having an orifice through which fluent moldingmaterial is delivered; and removal means including means for maintainingengagement of the solid molding material with the die of said firstpress member during separation of the press members, means forcompletely-removing the solid molding material from said first pressmember, a vertical die protecting cover for covering the upper portionof the second die, and means for moving said cover into the spacebetween the press members and adjacent the face of the die of saidsecond press member to prevent contact of the removed solid moldingmaterial with said second press member. p

5. In a molding press, the combination offirst and second relativelymovable press members, each having a die, the die of said second pressmember having an orifice in its face through which fluent moldingmaterial is delivered; and removal means including means for maintainingengagement of the solid molding material with the die of said firstpress member during separation of the press members, spnle cutter means,and means for moving said sprue cutter means across the face of the dieof said second press member for severing the resultant sprue threadpulled by movement of the solid sprue from said orifice upon separationof the press members.

6. In a horizontal injection molding press, the combination of first andsecond relatively movable press mem-' bers, each having a die, the dieof said second press member having an on'ficein the face thereof throughwhich fluent molding material is delivered; and removal means forcompletely disengaging the solid molding material from the die of thefirst press member when the press members are parted including a powermeans, die protecting means operably connected to said power means formovement into the space between said press members when parted andalongside said second press member to preventsolid materialtromcontacting the die face of said Second m e -1 pm m al-brsaid. remova9 means, and sprue cutter means movable by said power means into slidingengagement with the die face of said second press member to cleanlysever the resultant sprue thread extending from said orifice.

7. In a horizontal injection molding press, the combination of first andsecond relatively movable press members each including a die; ejectionmeans mounted in the first press member, the die of the second pressmember having an orifice in the face thereof through which fluentmolding material is delivered; and a stripper mechanism positioned foraccess of the space between said press members when parted includingpower means, a comb mounted on said power means for movement into saidspace for stripping solid molding material from said ejection means uponrelative movement therebetwe'en, a die protecting cover operablyconnected to said power means for movement into said space to interruptthe trajec'tion of ejected and stripped solid material and therebyprevent its contact with the die face of said second press member, asprue cutter mounted on said die protecting cover and extending towardsaid die face, and means connected to said die protecting cover forbiasing said sprue cutter into slidable engagement with said die faceand over said orifice to cleanly sever the resultant 'sprue thread. i

8. In a horizontal injection molding press, the combination of first andsecond relatively movable press members each including a die; ejectionmeans mounted in the first press member for movement between an extendedposition and a reset position, the die of the second press member havingan orifice in the face thereof through which fluent molding material isdelivered; and a stripper mechanism positioned for access of the spacebetween said press members when parted including power means, said powermeans having guide means mounted therein, a carriage slidably mounted insaid guide means and means connected to said carriage for transverselyreciproeating the carriage toward and away from said space, a combmounted on said carriage for movement into said space for strippingsolid molding material from said ejection means upon movement of saidejection means to said reset position, a die protecting cover pivotallymounted on said carriage and movable therewith into said space tointerrupt the trajection of ejected and stripped solid material andthereby prevent its contact with and residence on the die face of saidsecond press member, a sprue cutter mounted on said die protecting coverand extending toward said die face, and means connected to said dieprotecting cover for biasing said sprue cutter into slidable engagementwith said die face and over said orifice to cleanly sever the resultantsprue thread.

9. In a horizontal injection molding press, the combination of first andsecond relatively movable press members each including a die; ejectionmeans mounted in the first press member for movement between an extendedposition and a reset position, the die of the second press member havingan orifice in the face thereof through which fluent molding material isdelivered; and a stripper mechanism positioned for access of the spacebetween said press members when parted including power means, a combmounted on said power means for movement into said space for strippingsolid molding material from said ejection means upon movement of saidejection means to said reset position, a cutter blade mounted on saidcomb for severing a desired molded article from its gate prior toengagement of the remaining solid molding material with said comb, and adie protecting cover operably connected to said power means for movementinto said space to interrupt the trajection of ejected and strippedsolid material and thereby prevent its contact with the die face of saidsecond press member.

10. In a horizontal injection molding press, the combination of firstand second relatively movable press members each including a die;ejection means mounted in the first press member for movement between anextended position and a reset position, the die of the second pressmember having an orifice in the face thereof through which fluentmolding material is delivered; and a stripper mechanism positioned foraccess of the space between said press members when parted includingpower means, a comb mounted on said power means for movement into saidspace for stripping solid molding material from said ejection means uponmovement of said ejection means to said reset position, a cutter blademounted on said comb for severing a desired molded article from its gateprior to engagement of the remaining solid molding material with saidcomb, a die protecting cover operably connected to said power means formovement into said space to interrupt the trajection of ejected andstripped solid material and thereby prevent its contact with the dieface of said second press member, a sprue cutter mounted on said dieprotecting cover and extending toward said die face, and means connectedto said die protecting cover for biasing said sprue critter intoslidable engagement with said die face and over said orifice to cleanlysever the resultant sprue thread.

11.- In a horizontal injection molding press, the combination of firstand second relatively movable press members each including a die;ejection means mounted in the first press member for movement between anextended position and a reset position, the die of the second pressmember having an orifice in the face thereof through which fluentmolding material. is'delivered; and a stripper mechanism positionedforaccess of the space between said press members when parted includingpower means, said power means having guide means mounted therein, acarriage slidably mounted in said guide means and means connected tosaid carriage for transversely recipmeeting the carriage toward and awayfrom said space, a comb mounted on said carriage for movement into saidspace for stripping solid molding material from said ejection means uponmovement of said ejection means to said reset position, a cutter blademounted on said comb for severing a desired molded article from its gateprior to engagement of the remaining solid molding material wih saidcomb, and a die protecting cover pivotally mounted on said carriage andmovable therewith into said space to interrupt the trajection of ejectedand stripped solid material and thereby prevent its contact with the dieface of said second press member.

12. In a horizontal injection molding press, the combination of firstand second relatively movable press members each including a die;ejection means mounted in the first press member for movement between anextended position and a reset position, the die of the second pressmember having an orifice in the face thereof through which fluentmolding material is delivered; and a stripper mechanism positioned foraccess of the space between said press members when parted includingpower means, said power means having guide means mounted therein, acarriage slidably mounted in said guide means and means connected tosaid carriage for transversely reciprocating the carriage toward andaway'from said space, a comb mounted on said carriage for movement intosaid space for stripping solid molding material from said ejection meansupon movement of said ejection means to said reset position, a cutterblade mounted on said comb for severing a desired molded article fromits gate prior to engagement of the remaining solid molding materialwith said comb, a die protecting cover pivotally mounted on saidcarriage and movable therewith into said space to interrupt thetrajection of ejected and stripped solid material and thereby preventits contact with the die face of said second press member, a spruecutter mounted on said die protecting cover and extending toward saiddie face, and means connected to said die protecting cover for biasingsaid sprue cutter into slidable engagement with said die face and oversaid orifice to cleanly sever the resultant sprue thread.

13. In an injection molding press, the combination of first and secondrelatively movable press members, the first press member including afirst die, the second press member including a second die, a moldingcavity defined 11 between said dies, a gate passage definedbetween saiddies leading to said cavity, an orifice in the face of said second diethrough which fluent molding material is delivered to said gate passage,whereby said press forms an integral solid molded piece including adesired molded article in said cavity, a gate portion in said gatepassage and a sprue in said orifice, a die protecting cover positionedfor movement between said press members when parted, a sprue cuttermounted on said die protecting cover, means connected to said cover formoving said cover over the face of said second die to prevent removedsolid molding material from contacting said second die and for movingsaid sprue cutter into slidable engagement with the face of said seconddie to cleanly sever the resultant sprue thread extending from saidorifice, ejection means movably mounted in the first press member forpushing the molded article away from the face of the first die when thepress members are'parted, said first die having gate restraining meansfor delaying complete movement of the gate portion upon the initialpushing action of the ejection means whereby the joint between said gateportion and the desired molded article is broken.

14. In an injection molding press the combination of first and secondrelatively movable press members, the first press member including afirst die, thesecond press member including a second die, a moldingcavity defined between said dies, a gate passage defined between saiddies leading to said cavity, an .angularly disposed hole in the face ofsaid first die leading to said gate passage, an orifice in said seconddie through which fluent molding material is delivered to said gatepassage, whereby said press forms an integral solid molded pieceincluding a desired article in saidcavity, a gate portion in said gatepassage, a gate restraining portion in said angular hole and a sprue insaid orifice; and ejection means mounted in said first press membercomprising a sprue base holder for engaging said solid molded piece andan ejector pin for engaging and moving the desired molded article awayfrom the face of the first die when the press members are parted, saidsprue base holder and ejector pin being slidably mounted in said firstdie, said sprue base holder maintaining the solid molding material inposition atthe first die during separation of the press members, andmeans for moving the sprue base holder and the ejector pin beyond theface of the first die whereby the desired molded article is broken fromits gate portion which is initially restrained from complete movement byresidence of said gate restraining portion in said angularly disposedhole.

References Cited in the file of this patent UNITED STATES PATENTS

